A number of devices and methods are known for securing information on articles. See for example, U.S. Pat. Nos. 4,980,222 and 5,770,283.
One example of such a device for securing information is a scratch-off lottery card or ticket. The secured information (such as a winning number to be hidden) is printed on the card, and then covered with a scratch-off layer during manufacture of the card. The recipient of the card (such as a purchaser) scratches off the scratch-off layer with a coin, fingernail or the like, thus revealing the hidden number.
Not only does the scratch-off layer produce debris, but also the scratching process potentially damages the secured printed information underneath the scratch-off layer. When the hidden number matches the winning number (which may be widely known), the person who has bought the winning card and scratched off the layer to reveal the hidden winning number wins a prize. The winning number needs to be secured before the lottery ticket leaves the secure manufacturing site of the tickets. Even when the winning number is kept secret before its announcement, it is still necessary to secure the winning number on the card because the card might not yet be sold at the time of the announcement of the winning number. Otherwise, this could allow the winning ticket to be selectively purchased to win the prize.
This system of securing the secured information (e.g. the winning number on the lottery ticket) has the advantage that when the information is revealed, the card is irreversibly altered so that it is obvious that the secured information has been revealed. If the card is received in an altered state, that is, with the scratch-off layer missing or damaged, the card is void. Alternatively, a duplicate card could be printed including the winning number and a scratch-off coating applied over the number so as to duplicate the winning lottery ticket.
In addition to securing information, these devices may primarily serve to indicate when information has been accessed or when an object has been tampered with. Such devices are well known as tamper indicating devices, which may be adhered to a variety of objects. In general, tamper indicating devices are activated and changed irreversibly in some way when their removal from an object is attempted. These devices can provide security, for example, to the contents of a container. The container can be fastened with a tamper indicating device applied in such a way that when the container is opened, the device is activated and irreversibly changed. These changes are covertly or, more commonly, overtly detectable.
For example, a tamper indicating tape can be fastened across the flaps of a carton to close it and protect the contents of the container. Because such devices cannot be easily removed without activation, the device cannot be removed and re-adhered to another object, such as a counterfeit object without the replacement being detected.
One particular tamper indication device is a film such as a Tamper Evident Delaminating (TED) film, which utilizes a mixture of incompatible polymers such that when an attempt is made to remove the film (for example, in the form of adhesive tape) from a substrate (such as a sealed package) the film internally “delaminates,” causing the two polymers in the film to separate and split apart. See for example, U.S. Pat. No. 4,876,123.
Typically, devices of the art contain secured information, and therefore such devices need to be individually manufactured for each article when such information is unique to each article. There is a need for devices that can be used to secure information on objects when the information is already attached to the object in some way.